Numerical Study On Heat Transfer Characteristics Of Insulation And Cooling System Of Nuclear Pump

Nuclear power plant pump is a heat transfer medium in high temperature and high pressure environment.Under the large thermal load,it will have great impact on parts of nuclear pump bearing life,causing bearing failure,which triggered a nuclear accident.In order to let the transfer heat of the pump to the external environment and to the upper shaft seal and bearing within acceptable range,to ensure the safety and reliability of the pump group,the pump has heat insulation-cooling system.In this paper,the prototype of a centrifugal pump is taken as the research object,and the following contents are analyzed and calculated.(1)To introduce the function and operation condition of nuclear pump in nuclear power system,the research problem and research status of nuclear pump,and the research contents and research significance.(2)To introduce the structure of nuclear heat insulation-cooling system,the heat transfer calculation model of nuclear pump and the flow-solid coupling calculation method of flow and heat transfer(3)Geometrical modeling and meshing,fluid solid properties and boundary condition setting,solution setting and convergence conditions for nuclear pump insulation and cooling system are carried out.The temperature of each monitoring point obtained by numerical simulation under the corresponding working conditions is compared with the experimental data.It was found that the two groups had smaller values.It can be determined that the calculation method can well predict the temperature distribution of the cooling and cooling system of the nuclear pump,which is in good agreement with the experimental data.(4)The influence of the cooling gas parameters(including the temperature of the cooling gas and the velocity of the exhaust port)on the temperature of the shaft end is studied.The conclusion is that the temperature of the cooling gas is linear with the temperature of the axial cross section,and the temperature at the end of the shaft decreases with the decrease of the cooling gas temperature.With the increase of the gas velocity of the cooling gas inlet port,the temperature at the shaft end decreases,but they are not linear,and the temperature at the end of the shaft decreases less and less.In addition,In addition,the cooling gas suction flow rate is set to 0,then get the shaft end and the pump cover section temperature distribution cloud,from the results we know that the shaft temperature and pump cover temperature are higher than the design requirements of the temperature.It can be seen that the cooler can improve the heat transfer efficiency by forced air cooling,so as to achieve the design requirements of the temperature of the pump cover and pump shaft end.(5)The influence of the cooler radiator on the heat transfer of the nuclear pump is studied.The results show that the cooler radiator play a certain role in strengthening the heat dissipation and reducing the temperature of the shaft end.With the increase of the height of the cooler radiator,the starting temperature decreases greatly,and then the reduction rate gradually becomes smaller,until the final tends to be gentle.When the height of the cooler radiator is greater than 21cm,it has no heat dissipation effect,so the height of the cooler radiator can be set to 21cm.(6)The influence of the shield fins on the heat transfer characteristics of the nuclear pump was studied.From the calculation results,we can see that the shielding fin has great influence on the heat transfer characteristics of the nuclear pump,which can weaken the heat transfer of the high temperature medium.And if we increase the layers of the shielding fins,the effect will be better.On the basis of the above contents,this paper summarizes a set of thermal balance calculation method for a certain type of centrifugal pump prototype,and has been verified by experiments to ensure the stability and reliability of the method.Later studies of the pump can rely on the heat balance calculation method summarized in this paper.The influence of the insulation-cooling parameters,the parameters of the cooler radiator and the number of fins of shielding sleeve on the heat transfer characteristics of the nuclear pump can be used to provide a useful reference for the design of the pump.